Mawson placed so much pressure on victim Bryan Knox's neck that he crushed it and killed him
A former cage fighter killed a dad using his "party piece" choke hold after the victim accused him of making a pass at his partner.
Killer Thomas Gary Mawson had agreed to a fight with victim Bryan Knox to settle their differences over something which happened years ago.
A court heard Mawson grabbed dad Mr Knox in a "rear naked choke hold", which was a favourite move of his as a fighter.
But he placed so much pressure on Mr Knox's neck, he crushed it and killed him.
Mawson, not realising the man was dead, body-slammed him to the ground then took a trophy photograph of him lying face down in undergrowth on a Washington industrial estate.
He had been accused of murder but prosecutors accepted a guilty plea to the lesser charge of manslaughter and Mawson, 36, was jailed for five years.
At the hearing at Newcastle Crown Court, Mr Knox's mum, Beverley Beresford, a foster carer, fought back tears as she told the court of the impact the loss of her son has had on her and her family.
She said: "We have got a life sentence of grief.
"My grandaughter says she wants to die so she can be with her daddy, it's just so devastating.
"He was my son and my baby and I've had to bury him.
"My grandchildren and his children are distraught."
Mr Knox's son, Luke, told how his dad had missed his 18th birthday.
He said: "It was a big milestone turning 18 and my dad was not there to share it.
"He was a brilliant dad and always there with love and support and I always thought I could go to him for advise throughout life.
"It still feels like a bad dream and I have been left with a hole in my heart forever."
The court heard Mr Knox, of Barmston, Washington, and Mawson, of Alwin, Rickleton, Washington had socialised in the past and had trained together at a gym.
Two or three years ago there was a suggestion Mawson had made a pass at Mr Knox's partner, Joanne, but she denied it at the time.
But in July last year Mr Knox brought the subject up again and set about trying to contact Mawson for a "straightener".
They ended up going to a back lane on Stephenson Industrial Estate, in Washington, to fight.
The two men exchanged blows and Mawson said he only used the deadly choke hold after Mr Knox armed himself with a hammer from his van.
Prosecutor Nick Dry said: "The defendant is a former cage fighter and is known to favour the rear naked choke hold, which involves being behind someone and using force on the neck.
"It sometimes causes temporary loss of consciousness but not serious injury if it is controlled and released.
"It had been something of a party piece of the defendant's, he used it on friends and in fights.
"He said he also body slammed Mr Knox to the ground. An image of the victim lying face down in the undergrowth was seen on the defendant's phone.
"It had been taken as a trophy photograph just before he rang others panicking because he couldn't wake him up."
Mr Knox, 32, was dead on arrival at hospital, the forceful pressure to his neck having broken a bone and cartilage in his neck.
Mrs Knox said she has been left with post traumatic stress disorder and feels guilty over her husband's death.
She said: "I blame myself for allowing him to leave that day and about what happened two or three years previously.
"The children have suffered agonising heartache and miss their father.
"I have lost my best friend, a wonderful father to my children and my soulmate."
Tim Roberts QC, for Mawson, said: "It was because of the presence of the hammer that he put him in the choke hold to get him to drop the hammer.
"He had used this at official contests in the past and it had not resulted in any fatality.
"He wishes to convey his unreserved apology for the grief he has inflicted on Mr Knox's family.
"It was a historic and unsubstantiated allegation and he believed it could be resolved by talking."
